1. One of the external factors affecting the effect of mechanical seals is the inaccuracy of mechanical processing.

There are many reasons for the inadequate machining accuracy, some of which are the inadequate machining accuracy of the mechanical seal itself, which is easy to attract people's attention and find out. But sometimes the processing accuracy of other parts of the pump is not enough, which is not easy to attract people's attention. For example: pump shaft, sleeve, pump body, sealing chamber and other reasons for inadequate accuracy. The existence of these reasons is very disadvantageous to the sealing effect of mechanical seals.

2. External factors affecting mechanical seal effect 2: Vibration is on the high side

The vibration of mechanical seals is too large, which eventually leads to the loss of sealing effect. However, the reason for the large vibration of mechanical seal is not the reason of mechanical seal itself. Other parts of pump are the source of vibration, such as unreasonable design of pump shaft, reason of processing, inadequate bearing accuracy, poor parallelism of coupling, large radial force and so on.

3. External factors affecting mechanical seal effect 3: large axial channeling of pump shaft

The sealing surface of mechanical seal must have a certain specific pressure, so as to play a sealing role, which requires the spring of mechanical seal to have a certain amount of compression, give a thrust to the mechanical seal face, rotate to make the sealing surface produce the required specific pressure. In order to ensure this specific pressure, mechanical seal requires that the pump shaft can not have too much channeling, mechanical seal in the use process can not withstand the axial force, if there is an axial force, the impact of mechanical seal is serious. Sometimes due to the unreasonable design of the axial force balancing mechanism of the pump and the reasons of manufacture, installation and use, the axial force is not balanced. Mechanical seals withstand an axial force, and the temperature of sealing gland will be higher during operation. For polypropylene medium, it will be melted at high temperature. Therefore, the sealing effect will be lost soon after the start of the pump. When the pump is stationary, there will be intermittent leakage at the sealing end.

4. External factors affecting mechanical seal effect 4: unreasonable setting of no auxiliary flushing system or auxiliary flushing system

The auxiliary flushing system of mechanical seal is very important. The auxiliary flushing system of mechanical seals can effectively protect the sealing surface and play the role of cooling, lubricating and washing away debris. Sometimes the designer does not reasonably configure the auxiliary flushing system to achieve the sealing effect. Sometimes, although the designer designs the auxiliary system, due to impurities in the flushing fluid, insufficient flow and pressure of the flushing fluid, and unreasonable design of the flushing outlet position, the sealing effect is also not achieved.